POS, ERP or Er 2 (thermometer not held in place)

The thermometer was not held where it needs to be: not steady in the ear canal, held against the skin when it should hover, or held too far away. It refuses to give a reading rather than give a wrong one.

Check your thermometer’s manual — makers differ.

What it is for

Reposition and measure again as your manual shows. Braun (ThermoScan): “Take care that the positioning of the probe is correct and remains stable.” Microlife (IR 310): “Please insert the probe as described in this manual.” Microlife (NC 200): “Keep the measuring distance of 1 - 5 cm.”

These pages report what each maker’s manual says and quote it wherever health is involved. They do not diagnose anything, they are not medical advice, and they do not tell you whether a temperature is a fever or what to do about it; only your own thermometer’s manual and your doctor or nurse can do that for the person you are looking after.

What it looks like: Short letters such as POS or ERP instead of a reading, often with a run of short beeps; on Braun’s No touch, the characters 0 – 2 cm.
Names makers use: POS = position error (Braun ThermoScan); ERP, incorrect location indication (Microlife IR 310); Er 2, placed directly on the forehead (Microlife NC 200); 0 – 2 cm, move closer (Braun No touch BNT 400)

Where makes differ

Braun’s ThermoScan 7 sounds a sequence of short beeps and turns its ExacTemp light off before it shows POS. Microlife’s IR 310 also confirms a good position: it shows «good» with a short beep when the probe is in the right place. On forehead thermometers the problem is distance: Braun’s No touch BNT 400 shows “0 – 2 cm” when it is too far away, while Microlife’s NC 200 shows Er 2 when it touches the forehead.

What it does not mean

POS and ERP are not system faults and do not mean the thermometer is broken; a steadier, better-placed measurement clears them.

Other symbols with the same shapes

Lo on a thermometer (below the measuring range)The letters Lo, LO or just L where the number would be. Some…Hi on a thermometer (above the measuring range)The letters Hi, HI or just H where the number would be. Some…Err or Er with a number (thermometer error code)Err, ERR or Er with a number where the reading should be. Braun…M, memory number or memory icon (a stored reading)An M, sometimes with a number after it, or a small memory icon…Lens filter or probe cover symbol (cover missing)A small probe-cover or filter shape that blinks on an ear…Room too hot or too cold (AH, AL or ambient message)The letters AH or AL on Microlife thermometers; an error screen…

Sources

No published standard we could check defines the symbols on a digital thermometer’s display, so this meaning is taken from 2 makers’ own manuals and support pages, each fetched and read on the date shown:

Braun: Braun ThermoScan 7 (IRT 6520) and ThermoScan 3 (IRT 6030) infrared ear thermometers — instruction manual (Asia-Pacific, PDF) — “If the probe has NOT been constantly placed in a stable position in the ear canal, a sequence of short beeps will sound, the ExacTemp light will go out and the display will show an error message (POS = position error).” Checked 2026-09-29.
Braun: Braun No touch + forehead thermometer BNT 400 — instruction manual (Asia-Pacific, PDF) — “If the device is positioned too far away from the forehead, it will prompt you to move closer by displaying the characters “0 – 2 cm”.” Checked 2026-09-29.
Microlife: Microlife Ear Thermometer IR 310 — instruction manual (IB IR 310 N-V10, revision 2024-09-13, PDF) — Incorrect location indication: «ERP» “when the probe is not correctly inserted in the ear canal. Please insert the probe as described in this manual”; «Good» with a short beep at the correct position. Checked 2026-09-29.
Microlife: Microlife NC 200 non-contact thermometer — instruction manual (IB NC 200-e N-V10, 2026-08-17, PDF) — Error messages: «Er 2»: “Device is directly placed on the forehead / object. Keep the measuring distance of 1 - 5 cm.” Checked 2026-09-29.

Written in our own words; quotations are the makers’ wording.